Recapping Rates of Reaction (Kinetics)

Factors that affect Rate of Reaction


1) Temperature: When the temperature increases, the particles have increased kinetic energy, and therefore, they collilde more, and there are more successful collisions, and, more particles exceeding the activation energy. (Increased rate of reaction.)

2) Pressure: When the pressure is increased, there are more particles per a smaller space, so their is a higher likelihood or them colliding, and a therefore, and higher chance that there will be a successful collision. (Increased rate of reaction.)

3) Concentration: When the concentration is increased, there are more particles within the
space, meaning that there is a higher likelihood of collision, and a higher chance of successful collision. (Increased rate of reaction.)

4) Catalyst: A catalyst provide an alternate reaction pathway, that has a lower activation energy, more particles can exceed this activation energy, therefore, the rate of reaction will be quicker.

5) Surface Area: The parger the surface area, the more space upon which there is to react, therefore, more collisions can occur, so there will be a high rate of successful collisions: i.e. a higher rate of reaction.




Activation Energy Diagrams




Shows the enthalpy change. (The difference between products and reactants.) They also show how a catalyst lowers activation energy.)

Maxwell Boltzmann Curves show the number of particles against the energy of them. It shows that there are less amounts of particles with the energy to exceed the activation energy, or Ea.


The A2 Bit.

How do we measure rate?

• Measure the time it takes
• Collect gas -> Turn into moles using pV=nRT
• Measure the change in mass and then convert into moles. (n= Mr/Ar)

Rate is measured in mol dm-3 s-1. This mean moles per decimeter cubed per second.

The set up for a rate equation is Rate = k[A]x[B]y

K is called the constant rate, or the fiddle factor.

In two experiments, if the value you are focusing on doesn't change, and the end value doesn't either: factor O, if it does the same, e.g., they both double, it's factor 1, and if it does different i.e. it doubles and the end value quadruples, it's factor 2.

Essentially:

Zero- Changing the amount of this reactant has no effect on the rate.
One- Changing the amount of this reactant does the same to the rate. (Doubles both.)
Two- Changing the reactant does different to the rate - doubling the reactant quadruples the rate.

Thoughts?
-Nin.

(And do remember, I'm only a student myself, sorry if I get bits wrong. (: )